This is awesome, electronics knowledge and history is fascinating. These speakers are gorgeous! For those interested, these are high impedance speakers, and here's a bit more info into what that means. Impedance does not apply to DC voltage. Impedance is a concept used in AC (alternating current) circuits and is a measure of the opposition to the flow of AC current. It combines both resistance (which opposes the flow of current in both AC and DC circuits) and reactance (which opposes the flow of AC current specifically due to inductance and capacitance). A 1920's horn speaker typically requires a higher voltage to operate effectively. Impedance is essentially the opposition that a circuit presents to the flow of alternating current (AC), and a higher impedance means that less current will flow for a given voltage. To produce the same amount of power (which is a function of both current and voltage), a higher impedance speaker needs a higher voltage to compensate for the lower current. This relationship is described by Ohm's Law (V = I * R) and the power formula (P = V^2 / R), where V is voltage, I is current, R is impedance, and P is power. To produce the same power (1 watt) in an old RCA 1920s horn speaker with an assumed 4,000-ohm impedance, you would need approximately 63.25 volts, compared to the 2.83 volts needed for a modern 95 dB 8-ohm speaker.
Thanks for showing your collection of 1920's radios and speakers, which are extremely crude by today's standards but, highly a desired piece of technology in their day. I especially like the non-synchronized (2 or 3 tuning knob) tuned radios, where you had to keep a pad of paper by the radio to record the tuning knob settings for each radio station. The earliest radios would drive sensitive headphones only, because they had no amplification devices. When tube circuits (amplification devices) were later used, much more audio output power was available but, not enough to drive a modern speaker. I suspect the first horn speaker came about when someone placed a Victrola horn in front of a headphone, which is essentially what a horn speaker is. This opened up a whole new world, as more than one person at a time could listen to the radio. Horn speakers were refined over the years but, all had the same problem: Audio amplification is being accomplished acoustically, which causes a narrow frequency response. Horn speakers were barely adequate for voice but, poor for reproducing music. These early speakers were connected directly to the audio output circuit, between the plate of the tube and 90 volt battery (the power source used in the pre-1926 radios). There was no audio output transformer used at that time. Due to the DC bias on the voice coil, the magnet to diaphragm spacing took this bias caused offset into account, thus, the speaker had to be connected to radio in the correct polarity. Paper cone speakers were a vast improvement in sound quality over horn speakers but, needed more audio output power to drive them. Radio designers noticed this and redesigned the audio circuitry to increase output power starting in the latter 1920's. Paper cone speakers quickly obsoleted horn speakers. In the late 1930's, paper cone speakers were increasingly being refined, as well as the radio cabinet to further improve sound quality. The console radios used a 10 to 12 inch speaker and actuality can be considered "High Fidelity", even by today's standards.
@@curlyzim1Will-do on checking out your other videos. Since I have been restoring antique radios since the mid 1970's, thought I would add some history to hopefully add to the interest of your viewers.
@@curlyzim1 Wow, you have several antique radio videos - Nice! I also was bitten by the same "Radio Bug" as a young kid and ended up making a career of servicing and designing radios.
Thanks for the visual presentation of the horn-loudspeaker models made in the USA. I am a humble radio lover. There are old radio tube magazines, but when I tried to imagine how to make SUCH a CURVED DIFFUSER for my regenerative receiver, I was puzzled))). Damn, - "forbidden technologies of the ancient Americans")))) 73.
This is awesome, electronics knowledge and history is fascinating. These speakers are gorgeous! For those interested, these are high impedance speakers, and here's a bit more info into what that means.
Impedance does not apply to DC voltage. Impedance is a concept used in AC (alternating current) circuits and is a measure of the opposition to the flow of AC current. It combines both resistance (which opposes the flow of current in both AC and DC circuits) and reactance (which opposes the flow of AC current specifically due to inductance and capacitance).
A 1920's horn speaker typically requires a higher voltage to operate effectively. Impedance is essentially the opposition that a circuit presents to the flow of alternating current (AC), and a higher impedance means that less current will flow for a given voltage.
To produce the same amount of power (which is a function of both current and voltage), a higher impedance speaker needs a higher voltage to compensate for the lower current. This relationship is described by Ohm's Law (V = I * R) and the power formula (P = V^2 / R), where V is voltage, I is current, R is impedance, and P is power.
To produce the same power (1 watt) in an old RCA 1920s horn speaker with an assumed 4,000-ohm impedance, you would need approximately 63.25 volts, compared to the 2.83 volts needed for a modern 95 dB 8-ohm speaker.
This is so fascinating, thank you for uploading!
Interesting. Looks like they designed a lot of these speakers to work with a wide variety of radios/amps.
Thanks for showing your collection of 1920's radios and speakers, which are extremely crude by today's standards but, highly a desired piece of technology in their day. I especially like the non-synchronized (2 or 3 tuning knob) tuned radios, where you had to keep a pad of paper by the radio to record the tuning knob settings for each radio station.
The earliest radios would drive sensitive headphones only, because they had no amplification devices. When tube circuits (amplification devices) were later used, much more audio output power was available but, not enough to drive a modern speaker.
I suspect the first horn speaker came about when someone placed a Victrola horn in front of a headphone, which is essentially what a horn speaker is. This opened up a whole new world, as more than one person at a time could listen to the radio. Horn speakers were refined over the years but, all had the same problem: Audio amplification is being accomplished acoustically, which causes a narrow frequency response. Horn speakers were barely adequate for voice but, poor for reproducing music.
These early speakers were connected directly to the audio output circuit, between the plate of the tube and 90 volt battery (the power source used in the pre-1926 radios). There was no audio output transformer used at that time. Due to the DC bias on the voice coil, the magnet to diaphragm spacing took this bias caused offset into account, thus, the speaker had to be connected to radio in the correct polarity.
Paper cone speakers were a vast improvement in sound quality over horn speakers but, needed more audio output power to drive them. Radio designers noticed this and redesigned the audio circuitry to increase output power starting in the latter 1920's.
Paper cone speakers quickly obsoleted horn speakers. In the late 1930's, paper cone speakers were increasingly being refined, as well as the radio cabinet to further improve sound quality. The console radios used a 10 to 12 inch speaker and actuality can be considered "High Fidelity", even by today's standards.
@@billharris6886 Thanks for the nice comments🙏. Please check out my other antique radio videos in my playlist of Antique Radios.
@@curlyzim1Will-do on checking out your other videos. Since I have been restoring antique radios since the mid 1970's, thought I would add some history to hopefully add to the interest of your viewers.
@@curlyzim1 Wow, you have several antique radio videos - Nice! I also was bitten by the same "Radio Bug" as a young kid and ended up making a career of servicing and designing radios.
Thanks for the visual presentation of the horn-loudspeaker models made in the USA. I am a humble radio lover. There are old radio tube magazines, but when I tried to imagine how to make SUCH a CURVED DIFFUSER for my regenerative receiver, I was puzzled))). Damn, - "forbidden technologies of the ancient Americans")))) 73.
Thanks for watching. Good luck with your hobbies and projects.
73’s Mark
@@curlyzim1 Thank you Sir!))